This invention relates to tilting carrier conveyors of the type used to sort packages, parcels or the like and more particularly to an apparatus and method for tipping the carriers of such a conveyor or sortation system.
Tilting carrier conveyor systems are known and are shown, for example, in Speaker U.S. Pat. No. 3,945,485: Speaker et al U.S. Pat. No. 4,102,448; Venzke U.S. Pat. No. 4,174,773; and Prydtz U.S. Pat. No. 4,635,785. The general arrangement of such systems includes a track and a driven conveying chain or the like on which are mounted a number of carriers, spaced along the chain. Each carrier has a portion, often similar to a tray, which is mounted for normal positioning essentially horizontally level and for tipping to one, the other, or both sides of the direction of movement of the chain. Parcels or the like to be sorted are carried on the trays and transported by the conveyor to a location where sorting is to occur. At the sorting location, trays or carriers are tipped to one side or the other to discharge the transported article from the conveyor. Typically, control over tipping is exercised by some sortation controlling means such as a computer which controls a tipping device.
Prior tipping devices have been pneumatically actuated cylinder devices in which some striker element or the like is moved upwardly into the path of an advancing carrier, to engage an actuating cam or the like on the carrier and cause tipping. As sortation speeds have increased, and the linear speed of the chain and carriers have risen, difficulty has been encountered in operating a tipping device quickly enough to achieve proper sortation while retracting the device from the path of an oncoming carrier so as to avoid damage to the sortation system. Where the mechanism provided for retraction of a reciprocating tipping device fails to operate as needed, substantial damage to a conveyor system follows, such as by demounting, destroying, or seriously damaging a series of carriers which strike an improperly retracted or unretracted tipping device.